Sometimes, people do things that seem silly, strange, or hard to understand. When this happens, others might use funny or interesting phrases to describe them. These phrases are called idioms. Instead of saying someone is just acting strange, people might say something like “off their rocker” or “a few fries short of a Happy Meal.” These idioms make talking more fun and colorful.
In this article, we’ll learn about idioms people use when talking about someone acting a little wild or different. These aren’t meant to be mean. Many times, they are just jokes or fun ways to describe someone who’s doing something unexpected. Let’s take a look at some of the most common idioms used in these situations and what they really mean.
Idioms for Crazy
1. Off your rocker
Meaning: Acting very silly or strange
Example Sentence:
• Grandpa said I was off my rocker for putting ketchup on cereal.
• She must be off her rocker to wear flip-flops in the snow.
Other ways to say: Lost your mind, acting goofy
Fun Fact/Origin: It comes from the idea of a rocking chair moving without control.
Usage: Used when someone is acting in a surprising or odd way.
2. Not playing with a full deck
Meaning: Acting like something’s not quite right in their thinking
Example Sentence:
• He tried to ride his bike on the roof. He’s not playing with a full deck.
• That kid who talks to trees might not be playing with a full deck.
Other ways to say: Missing a few screws, not all there
Fun Fact/Origin: Comes from card games—missing cards means the game doesn’t work right.
Usage: Used when someone does things that don’t make sense.
3. A few fries short of a Happy Meal
Meaning: Someone who isn’t thinking clearly
Example Sentence:
• He wore his Halloween costume in July. A few fries short of a Happy Meal!
• She thinks dogs can drive cars—she’s missing some fries!
Other ways to say: Not quite right, silly
Fun Fact/Origin: McDonald’s Happy Meals come with fries. If some are missing, it’s incomplete.
Usage: Used to joke about someone who’s being strange.
4. Lost your marbles
Meaning: To act like you’ve gone a little crazy
Example Sentence:
• When he started dancing in the grocery store, I thought he’d lost his marbles.
• You lost your marbles if you think we can eat 50 tacos at once!
Other ways to say: Gone bananas, out of it
Fun Fact/Origin: Marbles were once a popular toy. Losing them meant losing control.
Usage: Said when someone acts in a weird or wild way.
5. Bats in the belfry
Meaning: Having strange or silly thoughts
Example Sentence:
• She’s got bats in the belfry if she thinks cats can read books.
• Talking to your sandwich? That’s some bats in the belfry.
Other ways to say: Loopy, odd
Fun Fact/Origin: A belfry is a bell tower. Bats flying around it makes a weird image.
Usage: Used when someone has weird ideas or acts silly.
6. Mad as a hatter
Meaning: Completely silly or wild
Example Sentence:
• He’s mad as a hatter for jumping into the pool in winter.
• She wore ten hats at once. Totally mad as a hatter.
Other ways to say: Bonkers, wacky
Fun Fact/Origin: Old hat makers used chemicals that made them sick and act strangely.
Usage: Used when someone’s behavior is very strange.
7. Off the wall
Meaning: Very odd or unexpected
Example Sentence:
• That’s an off-the-wall idea—using peanut butter as shoe polish!
• His jokes are really off the wall.
Other ways to say: Out there, bizarre
Fun Fact/Origin: It’s like something that bounced off the wall and didn’t land right.
Usage: Used for weird or wild behavior or ideas.
8. One sandwich short of a picnic
Meaning: Not thinking clearly or fully
Example Sentence:
• He put glue on his sandwich. One sandwich short of a picnic!
• If you think pigs can fly, you’re missing a sandwich.
Other ways to say: Not all there, lacking sense
Fun Fact/Origin: A picnic without a sandwich feels incomplete—just like a person acting odd.
Usage: Used to poke fun at someone’s strange ideas.
9. Cuckoo
Meaning: Crazy or acting wild
Example Sentence:
• She ran around the yard yelling at squirrels—cuckoo!
• If you wear socks on your hands, people might call you cuckoo.
Other ways to say: Nuts, wacky
Fun Fact/Origin: Comes from the sound of a cuckoo bird, which repeats the same sound.
Usage: Said about people acting in a way that’s hard to understand.
10. Looney tunes
Meaning: Acting very silly or crazy
Example Sentence:
• That plan to build a house out of jelly is looney tunes.
• You’re looney tunes if you think we can walk to the moon!
Other ways to say: Nutty, zany
Fun Fact/Origin: Comes from the cartoon series “Looney Tunes,” full of wild characters.
Usage: Used for funny or foolish behavior.
11. Gone bananas
Meaning: Acting super silly or excited
Example Sentence:
• He went bananas when he saw the giant pizza.
• The crowd went bananas when the singer appeared.
Other ways to say: Lost it, flipped out
Fun Fact/Origin: Bananas are yellow and bendy—just like how wild behavior can be unpredictable.
Usage: Used when someone gets overly excited or silly.
12. Nuts
Meaning: Crazy or not thinking clearly
Example Sentence:
• You’re nuts if you think you can skate on grass.
• She’s nuts for painting her room with glow-in-the-dark paint.
Other ways to say: Loopy, bonkers
Fun Fact/Origin: “Nuts” can also mean things that bounce or pop, like surprising actions.
Usage: Said when someone’s behavior seems a little wild.
13. Out to lunch
Meaning: Not paying attention or acting strange
Example Sentence:
• I said “hi” three times and she just stared. She’s out to lunch.
• If you think cats can take selfies, you’re out to lunch.
Other ways to say: Zoned out, distracted
Fun Fact/Origin: It means someone’s mind is far away, like they’re not there.
Usage: Used when someone is acting confused or spacey.
14. Bonkers
Meaning: Completely silly or wild
Example Sentence:
• He went bonkers when he saw the roller coaster.
• That idea is bonkers—making a pillow out of spaghetti!
Other ways to say: Crazy, out of control
Fun Fact/Origin: A fun word used to describe silly or wild behavior.
Usage: Used for crazy actions or thoughts.
15. Zany
Meaning: Funny in a weird or strange way
Example Sentence:
• The clown was zany with his big shoes and silly dance.
• That show is full of zany characters doing weird stuff.
Other ways to say: Silly, goofy
Fun Fact/Origin: Comes from old plays where the zany character was the silly helper.
Usage: Used when someone or something is fun but odd.
16. Lost it
Meaning: Suddenly started acting wild or emotional
Example Sentence:
• He lost it when he saw his broken video game.
• She lost it when the dog ran away with her shoe.
Other ways to say: Snapped, flipped out
Fun Fact/Origin: “Lost it” means losing control, like dropping something you were holding.
Usage: Used when someone can’t control their emotions.
17. Crack up
Meaning: To laugh a lot or act a little silly
Example Sentence:
• She cracked up during the spelling bee for no reason.
• He cracked up when he saw the funny video.
Other ways to say: Burst out laughing, go silly
Fun Fact/Origin: Comes from something “cracking,” or breaking down.
Usage: Used for someone who laughs too much or acts silly.
18. Out of your mind
Meaning: Not thinking clearly or doing something strange
Example Sentence:
• You’re out of your mind if you think I’ll eat that bug!
• He must be out of his mind to try jumping over a car.
Other ways to say: Nuts, wild
Fun Fact/Origin: Means your brain isn’t working the usual way.
Usage: Said when actions are way outside normal.
19. Wacky
Meaning: Funny in a silly or odd way
Example Sentence:
• That hat with horns is super wacky.
• The teacher wore a wacky tie with flying cows.
Other ways to say: Goofy, crazy
Fun Fact/Origin: Wacky sounds like “whack,” like something knocked out of place.
Usage: Used to describe silly things or people.
20. Off the deep end
Meaning: Acting in a really wild way
Example Sentence:
• He went off the deep end when he saw his birthday gift.
• She went off the deep end after her team lost.
Other ways to say: Flipped out, overreacted
Fun Fact/Origin: From diving into the deep end of a pool—sudden and extreme.
Usage: Used when someone reacts in a big, strange way.
21. Cookoo for Cocoa Puffs
Meaning: Acting wild or excited
Example Sentence:
• He’s cookoo for Cocoa Puffs about skateboarding.
• She’s cookoo for Cocoa Puffs over that new movie.
Other ways to say: Obsessed, nuts
Fun Fact/Origin: From a cereal ad where the character acted silly with excitement.
Usage: Used in fun ways when someone is super into something.
22. Batty
Meaning: A little bit crazy or odd
Example Sentence:
• That idea to build a robot from forks is batty.
• He’s a little batty about aliens.
Other ways to say: Loony, silly
Fun Fact/Origin: Comes from the word “bat,” like bats flying oddly.
Usage: Said in a fun way when someone is quirky.
23. Round the bend
Meaning: Acting like you’ve gone crazy
Example Sentence:
• He’s gone round the bend, talking to plants again.
• That project made her go round the bend.
Other ways to say: Lost it, flipped out
Fun Fact/Origin: Comes from a path turning unexpectedly—like behavior changing suddenly.
Usage: Used when someone acts very strangely.
24. Not all there
Meaning: Not fully thinking clearly
Example Sentence:
• He’s not all there today—he wore two different shoes!
• She forgot her own name. I think she’s not all there.
Other ways to say: Spaced out, confused
Fun Fact/Origin: Suggests part of someone’s thoughts are missing.
Usage: Used when someone seems distracted or odd.
25. A screw loose
Meaning: Something seems off or not working right mentally
Example Sentence:
• He’s got a screw loose if he thinks a cat can drive.
• That plan has a screw loose—it makes no sense!
Other ways to say: Not right in the head, a bit off
Fun Fact/Origin: Comes from machines where loose screws cause problems.
Usage: Used when things don’t add up with someone’s behavior.
26. Bonzo
Meaning: Acting extremely wild or silly
Example Sentence:
• He went bonzo over that new video game.
• She gets bonzo when there’s candy around.
Other ways to say: Crazy, nuts
Fun Fact/Origin: Sounds like a silly cartoon word.
Usage: Used for wild excitement.
27. Off the chain
Meaning: Acting really out of control or wild
Example Sentence:
• That party was off the chain!
• He went off the chain when his team won.
Other ways to say: Over the top, nuts
Fun Fact/Origin: Comes from dogs breaking free from chains and running wild.
Usage: Used when someone is acting extra loud or wild.
28. Loopy
Meaning: Acting dizzy or silly
Example Sentence:
• She got loopy from too much cotton candy.
• He was loopy after spinning around too fast.
Other ways to say: Goofy, wacky
Fun Fact/Origin: Comes from “loop,” like someone going in circles.
Usage: Used when someone is being silly or confused.
29. Nuts and bolts missing
Meaning: Not quite right in the head
Example Sentence:
• That robot costume has its nuts and bolts missing—just like its maker!
• He’s acting like he’s got some bolts missing.
Other ways to say: Off, weird
Fun Fact/Origin: Comes from machines missing important parts.
Usage: Used when someone seems a bit off.
30. Out of whack
Meaning: Not working or behaving normally
Example Sentence:
• My brain’s out of whack after that puzzle.
• The clock’s out of whack—and so is my brother!
Other ways to say: Off balance, not right
Fun Fact/Origin: “Whack” means hit—so something out of whack may be hit wrong.
Usage: Used for strange behavior or things not working right.
31. Screwy
Meaning: Weird or not making sense
Example Sentence:
• That idea to glue jellybeans to a skateboard is screwy.
• He’s acting a bit screwy today.
Other ways to say: Odd, bizarre
Fun Fact/Origin: Like screws being loose or turned wrong.
Usage: Used when something’s just strange.
32. Berserk
Meaning: Acting wildly or without control
Example Sentence:
• He went berserk when he lost his toy.
• Don’t go berserk just because it’s raining.
Other ways to say: Crazy, over the top
Fun Fact/Origin: From old Viking fighters who acted wild in battle.
Usage: Used when someone reacts wildly.
33. Nutty as a fruitcake
Meaning: Very silly or odd
Example Sentence:
• That guy dancing with balloons is nutty as a fruitcake.
• She’s nutty as a fruitcake for building a robot out of cookies.
Other ways to say: Bonkers, zany
Fun Fact/Origin: Fruitcake is packed with nuts and fruit—very mixed up.
Usage: Used in a fun way to call someone silly.
34. Offbeat
Meaning: Different or unusual in a fun way
Example Sentence:
• His music is kind of offbeat but cool.
• That outfit is offbeat—but she rocks it!
Other ways to say: Unique, quirky
Fun Fact/Origin: Comes from music where the beat is unexpected.
Usage: Used for creative or odd styles.
35. Cray-cray
Meaning: Acting very silly or wild (slang)
Example Sentence:
• That dog is cray-cray—it runs in circles all day!
• He’s acting cray-cray over a snack.
Other ways to say: Goofy, bonkers
Fun Fact/Origin: A silly way to say “crazy” repeated twice.
Usage: Used playfully, mostly by kids.
36. Out of touch
Meaning: Not understanding what’s normal
Example Sentence:
• He’s out of touch if he thinks kids still use flip phones.
• That idea is totally out of touch.
Other ways to say: Not with it, clueless
Fun Fact/Origin: Means someone isn’t keeping up with what others know.
Usage: Used when someone seems behind or weird.
37. Quirky
Meaning: Unusual in a fun way
Example Sentence:
• Her quirky style includes wearing two different shoes.
• That movie was quirky but fun.
Other ways to say: Odd, offbeat
Fun Fact/Origin: “Quirk” means a small strange habit.
Usage: Used when someone is different, but fun.
38. Kooky
Meaning: Funny and strange
Example Sentence:
• That lady who talks to her plants is kind of kooky.
• He’s a kooky kid with his upside-down backpack.
Other ways to say: Wacky, nutty
Fun Fact/Origin: A lighthearted word to call someone silly.
Usage: Said when someone acts a little weird in a cute way.
39. Out of it
Meaning: Not paying attention or feeling spacey
Example Sentence:
• I was out of it after staying up too late.
• He’s out of it today—he tried to open his locker with a spoon!
Other ways to say: Zoned out, spaced
Fun Fact/Origin: Means your brain feels far away.
Usage: Used when someone seems tired or dazed.
40. Touched in the head
Meaning: Acting strange
Example Sentence:
• That guy who sings to his cereal might be touched in the head.
• She’s a little touched for wearing ten scarves in summer.
Other ways to say: Loopy, odd
Fun Fact/Origin: A gentle way people used to describe strange behavior.
Usage: Used in old-fashioned or silly ways.
41. Eccentric
Meaning: Very different from others
Example Sentence:
• That artist is eccentric—he paints with noodles!
• Her house is eccentric, with pink grass.
Other ways to say: Quirky, unusual
Fun Fact/Origin: Comes from science—it means off-center.
Usage: Used for people who are different in cool or strange ways.
42. Whacky-doodle
Meaning: Very silly or out there
Example Sentence:
• That story about flying penguins is whacky-doodle.
• He had a whacky-doodle plan to ride a skateboard on snow.
Other ways to say: Nuts, loony
Fun Fact/Origin: A made-up word to sound funny and strange.
Usage: Used when something sounds like nonsense.
43. Go bananas
Meaning: Act crazy or overly excited
Example Sentence:
• He went bananas when school was canceled.
• The dog went bananas when it saw the ball.
Other ways to say: Lose it, get wild
Fun Fact/Origin: Bananas are often used in silly phrases.
Usage: Used when excitement turns wild.
44. Screwball
Meaning: A person who acts in a very silly or odd way
Example Sentence:
• That guy dressed like a wizard is a screwball.
• She’s a total screwball, always telling weird jokes.
Other ways to say: Nut, clown
Fun Fact/Origin: A screwball is also a type of pitch in baseball—unexpected.
Usage: Used when someone acts silly or out of the norm.
45. Not right in the head
Meaning: Acting in a way that seems strange or wrong
Example Sentence:
• He’s not right in the head if he thinks he can fly.
• That plan isn’t right in the head—it involves 20 pizzas and a trampoline.
Other ways to say: Crazy, wild
Fun Fact/Origin: A phrase used to say something’s a little off in thinking.
Usage: Used when someone’s idea or action seems way off.
Quiz: Idioms for Crazy
Instructions: Read each question and the answer choices carefully. Pick the letter that best matches the meaning of the phrase or expression.
Question Key
1. What does “off your rocker” mean?
A) Sitting in a chair
B) Acting very silly or strange
C) Taking a nap
2. If someone is “not playing with a full deck,” what are they doing?
A) Playing cards well
B) Acting strangely or not thinking clearly
C) Cleaning the table
3. What does it mean if a person has “lost their marbles”?
A) They dropped a toy
B) They forgot something important
C) They are acting like they lost their mind
4. What does “a few fries short of a Happy Meal” describe?
A) Someone who’s hungry
B) A person who’s acting a little odd
C) A meal with no drink
5. If someone is “batty,” what does that mean?
A) They play baseball
B) They act a bit strange or silly
C) They like animals
6. What does “gone bananas” mean?
A) They are eating fruit
B) They are going grocery shopping
C) They are acting super silly or excited
7. If your friend is “off the wall,” how are they acting?
A) Very normal
B) Very odd or unexpected
C) Very quiet
8. What does it mean to “go off the deep end”?
A) To dive in a pool
B) To act in a really wild way
C) To learn how to swim
9. If someone is “crackin’ up,” what are they doing?
A) Breaking something
B) Laughing a lot or acting silly
C) Being serious
10. What does “cuckoo” mean in this idiom list?
A) A smart person
B) A bird
C) A person acting crazy or silly
11. What does it mean if someone is “out to lunch”?
A) They are eating food
B) They are not paying attention or acting strange
C) They are at school
12. What does “nutty as a fruitcake” mean?
A) Tastes sweet
B) Acts wild and silly
C) Bakes a lot
13. If someone is “loopy,” what does it mean?
A) They are walking in circles
B) They are acting silly or dizzy
C) They are drawing
14. What does “not all there” mean?
A) The person hasn’t arrived yet
B) They left something at home
C) They seem a little confused or off
15. What does “wacky” describe?
A) Something boring
B) Something silly or strange
C) Something loud
Answer Key
- B) Acting very silly or strange
- B) Acting strangely or not thinking clearly
- C) They are acting like they lost their mind
- B) A person who’s acting a little odd
- B) They act a bit strange or silly
- C) They are acting super silly or excited
- B) Very odd or unexpected
- B) To act in a really wild way
- B) Laughing a lot or acting silly
- C) A person acting crazy or silly
- B) They are not paying attention or acting strange
- B) Acts wild and silly
- B) They are acting silly or dizzy
- C) They seem a little confused or off
- B) Something silly or strange
Wrapping Up
People say all kinds of fun things to describe strange behavior. Instead of saying someone is acting crazy, these idioms use silly pictures and jokes. They help us laugh and understand how someone is feeling or acting. You’ve now learned 45 idioms that show how words can be playful and smart at the same time.
Next time someone acts a little wild or goofy, try using one of these idioms. Just remember to use them kindly and not to hurt someone’s feelings. Words can be fun—but they should also be used in a good way.
